The present invention relates generally to a method of modulating cellular activity and agents useful for same. More particularly, the present invention contemplates a method of modulating endothelial cell activity and even more particularly endothelial cell adhesion molecule expression. Most particularly, the present invention provides a method of treating coronary heart disease by preventing or reducing endothelial cell adhesion molecule expression.
Bibliographic details of the publications referred to by author in this specification are collected at the end of the description. Sequence Identity Numbers (SEQ ID NOs.) for the nucleotide and amino acid sequences referred to in the specification are defined immediately before the bibliography.
Atherosclerotic coronary heart disease is one of the major causes of death in the western world (World Health Statistics Annual). An earlier event in atherogenesis is the adhesion of monocytes to the endothelium via adhesion molecules such as VCAM-1, ICAM-1 and E-selectin, all of which are rapidly synthesised in response to cytokines. VCAM-1 is primarily involved in the adhesion of mononuclear leukocytes to the endothelium. It is rapidly induced by the inflammatory cytokines IL-1 and TNF-xcex1, and its induction is sustained for 49 to 72 hours. ICAM-1 is expressed on many cells types and is involved in both monocyte and lymphocyte adhesion to activated endothelium. E-selectin is an endothelial specific adhesion molecule important in capturing leukocytes from the axial stream to roll along the endatheliurn (Abbassi et al., 1993).
There is considerable evidence for the involvement of adhesion molecules in the development of early atherosclerotic lesions and in mature atherosclerotic plaques (Van der Wal et al., 1992). Variable and low levels of E-selectin and VCAM-1 have been detected in the arterial endothelium over plaques (Van der Wal et al., 1992; Wood et al., 1993). VCAM-1 has also been observed in areas of neovasculatization and in inflammatory infiltrates at the base of plaques, suggesting that intimal neovascularization may be an important site of inflammatory cell recruitment into advanced coronary lesions (O""Brien et al., 1993). ICAM-1 has been shown to be expressed on the endothelium overlaying atheromatous plaques (Johnson-Tidey et al., 1994).
The signals that lead to upregulation of cellular activities such as expression of adhesion molecules have not been defined. Elucidating these cellular signalling mechanisms is necessary for the development of therapeutic strategies to disease conditions in which said cellular activities are harmful such as coronary heart disease and inflammatory conditions.
In work leading up to the present invention, the inventors have identified a sphingosine kinase signalling pathway via which cellular activities such as adhesion molecule expression are achieved. By regulating the expression and activity of individual components of this pathway, these cellular activities can be modulated. The inventors have also developed a rapid, high volume assay for detecting agents exhibiting sphingosine kinase activity and agents which can act as agonists and antagonists of sphingosine kinase activity.
Throughout this specification and the claims which follow, unless the context requires otherwise, the word xe2x80x9ccomprisexe2x80x9d, and variations such as xe2x80x9ccomprisesxe2x80x9d and xe2x80x9ccomprisingxe2x80x9d, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.
One aspect of the present invention relates to a method of modulating cellular activity in a mammal said method comprising administering to said mammal an effective amount of an agent for a time and under conditions sufficient to modulate the activity of one or more components of a sphingosine kinase signalling pathway.
Another aspect of the present invention provides a method of modulating adhesion molecule expression in a mammal said method comprising administering to said mammal an effective amount of an agent for a time and under conditions sufficient to modulate the activity of one or more components of a sphingosine kinase signalling pathway.
Yet another aspect of the present invention provides a method of modulating adhesion molecule expression in a mammal said method comprising administering to said mammal an effective amount of an agent for a time and under conditions sufficient to modulate the activity of one or both of sphingosine kinase and/or Sph-1-P.
Still another aspect of the present invention relates to a method of modulating endothelial cell adhesion molecule expression in a mammal said method comprising administering to said mammal an effective amount of an agent for a time and under conditions sufficient to modulate the activity of one or more components of a sphingosine kinase signalling pathway.
Still yet another aspect of the present invention provides a method of downregulating endothelial cell adhesion molecule expression in a mammal said method comprising administering to said mammal an effective amount of an agent for a time and under conditions sufficient to downregulate the activity of one or both of sphingosine kinase and/or Sph-1-P.
A further aspect of the present invention relates to a method of modulating adhesion molecule expression in a mammal said method comprising administering to said mammal an effective amount of one or more components of a sphingosine kinase signalling pathway or functional equivalents thereof.
Another further aspect of the present invention relates to a method of treatment or prophylaxis of a disease condition involving inflammatory mechanisms said method comprising administering to said mammal an effective amount of an agent for a time and under conditions sufficient to modulate the activity of one or more components of a sphingosine kinase signalling pathway wherein said modulation results in modulation of adhesion molecule expression.
Still another further aspect of the present invention provides a method of treating a mammal exhibiting coronary heart disease said method comprising administering to said mammal an effective amount of an agent for a time and under conditions sufficient to downregulate the activity of one or more components of a sphingosine kinase signalling pathway wherein said downregulation results in downregulation of endothelial cell adhesion molecule expression.
Still yet another further aspect of the present invention provides a method of treatment or prophylaxis of a disease condition involving inflammatory mechanisms said method comprising administering an effective amount of one or more components of a sphingosine kinase signalling pathway or functional equivalents thereof to said mammal.
In still yet another further aspect the present invention relates to the use of an agent capable of modulating the activity of one or more components of a sphingosine kinase signalling pathway in the manufacture of a medicament for the modulation of adhesion molecule expression in a mammal.
Another aspect of the present invention relates to the use of one or more components of a sphingosine kinase signalling pathway or functional equivalents thereof in the manufacture of a medicament for the modulation of adhesion molecule expression in a mammal.
Yet another aspect of the present invention relates to agents for use in modulating one or more components of a sphingosine kinase signalling pathway wherein modulating said components modulates adhesion molecule expression.
Yet another aspect of the present invention relates to one or more components of a sphingosine kinase signalling pathway or functional equivalents thereof for use in modulating adhesion molecule expression in a mammal.
Still another aspect of the present invention relates to a pharmaceutical composition comprising an agent capable of modulating one or more components of a sphingosine kinase signalling pathway wherein said modulation results in modulation of adhesion molecule expression, together with one or more pharmaceutically acceptable carriers and/or diluents.
Still yet another further aspect of the present invention relates to a pharmaceutical composition comprising one or more components of a sphingosine kinase signalling pathway or functional equivalents thereof together with one or more pharmaceutically acceptable carriers and/or diluents.
A further aspect of the present invention provides a method of detecting an analyte structurally or functionally reactive with a lipid, said method comprising the steps of contacting either:
(i) said analyte which analyte is radio labelled; or
(ii) said analyte and a reporter molecule which reporter molecule is radio labelled, said analyte being contacted with said lipid simultaneously with or separately to said reporter molecule;
with said lipid in the presence of a scintillant for a time and under conditions sufficient for a lipid-radio label complex to form and to excite said scintillant, and detecting said excited scintillant.
Another further aspect of the present invention relates to a method of detecting an analyte structurally or functionally reactive with sphingosine, said method comprising the steps of contacting either:
(i) said analyte which analyte is radio labelled; or
(ix) said analytic and a reporter molecule which reporter molecule is radio labelled, said analyte being contacted with said sphingosine simultaneously with or separately to said reporter molecule;
with said lipid in the presence of a scintillant for a time and under conditions sufficient for a sphingosine-radio label complex to form and to excite said scintillant, and detecting said excited scintillant.
Still another further aspect of the present invention provides a method for detecting an analyte exhibiting sphingosine kinase activity, said method comprising the steps of contacting said analyte and 33JP-ATP with sphingonsine in the presence of a scintillant, said analyte being contacted with said sphingosine simultaneously with or separately to said 33P-ATP, for a time and under conditions sufficient for 33P-sphingosine complex to form and to excite said scintillant, and detecting said excited scintillant.